Spoke Length Long Shot

[Hugh Manatee]

I gone broke ma spoke. I have looked at a couple of spoke length calculators and have had a couple of different answers. My main problem is I cannot see the exact hub/rim combo.

Does anyone have this combination and happen to have the specs written down?

Hub: Shimano 600 FH-6402 with a nine speed cassette. I only found reference to eight speed.
Rim: Mavic Open 4CD

36 spokes in three cross. It is the non drive side that has gone ping. I hate speed ramps!

Thanks in advance.

 

[midlife]

Measure the broken spoke?

Shaun

 

[midlife]

Measure the broken spoke?

Shaun

 

[accountantpete]

Take another one off and measure from the elbow to the end of the thread.

( You can count the number turns needed to remove the nipple and then repeat when putting it back on).

 

[RebornBumbler]

Take another one off and measure from the elbow to the end of the thread.
( You can count the number turns needed to remove the nipple and then repeat when putting it back on).

Agreed - take off the spoke opposite the broken one

 

[Hugh Manatee]

The measuring another spoke was always going to be my plan B. I don't have a lot of confidence when it comes to wheels. I'll have one go at truing it and if it doesn't work it'll be off to the LBS.

Thanks all.

 

[Yellow Saddle]

I gone broke ma spoke. I have looked at a couple of spoke length calculators and have had a couple of different answers. My main problem is I cannot see the exact hub/rim combo.

Does anyone have this combination and happen to have the specs written down?

Hub: Shimano 600 FH-6402 with a nine speed cassette. I only found reference to eight speed.
Rim: Mavic Open 4CD

36 spokes in three cross. It is the non drive side that has gone ping. I hate speed ramps!

Thanks in advance.

There you go.

Geometric length is 294.4mm
Round down by up to 1.5mm

Now say sorry to the speed ramp. It wasn't it that caused the spoke to break.

 

[Hugh Manatee]

Thanks @Yellow Saddle
One of the answers I got was within an ace of your figures. I will unleash a spare bike until I can get to the LBS. I hate the damn speed bumps with a passion. The feckless moron who did the design put a full width one right on a sharp bend. It broke as the wheel loaded. That and the fact that all drivers now play MGIF and then swing back in to avoid running over the half width cushions have actually made cycling a lot more dangerous than it used to be.

That and my spare car is basically trapped in the garage. It can't get out of the cul-de-sac. I'm thinking of buying something different next. A classic bulldozer perhaps?

Thanks again!

 

[Yellow Saddle]

Thanks @Yellow Saddle
One of the answers I got was within an ace of your figures. I will unleash a spare bike until I can get to the LBS. I hate the damn speed bumps with a passion. The feckless moron who did the design put a full width one right on a sharp bend. It broke as the wheel loaded. That and the fact that all drivers now play MGIF and then swing back in to avoid running over the half width cushions have actually made cycling a lot more dangerous than it used to be.

That and my spare car is basically trapped in the garage. It can't get out of the cul-de-sac. I'm thinking of buying something different next. A classic bulldozer perhaps?

Thanks again!

The problem with these online spoke calculators is that you don't have sight of what they're doing. By getting the actual geometric length, you know what you can work with and how to adapt the length to suit available stock.

Just as an aside. Hitting a speed ramp or landing after a jump, doesn't load the spoke but unload it, that's why I said it wasn't the ramp. The spoke was fatigued (and all the others are too) and the ramp was just the last straw. If you are convinced that the spoke actually broke at the ramp (a broken spoke is a non-event on 36-spoke wheels) at the ramp, then it broke just after hitting the ramp, when the wheel "loaded" again. Now that you are going to the trouble of buying one spoke, tests the others first. Put a hammer's handle or old left crank in between the crosses on the spokes and forcefully push on the lever until it touches the rim. That will break any spokes that would have broken soon, saving you a trip or two to the spoke shop.